Many optical communication systems manipulate light waves to carry information. For instance, often a light source (e.g., a laser source) is modulated to change various properties of emitted light, such as an amplitude, phase, or frequency of the light to convey information. In some cases, an underlying signal, such as a radio frequency signal, may be modulated via amplitude, phase, or frequency modulation, or any combination thereof, and the light source may be modulated by the underlying signal. Optical receivers receive the light waves and measure properties or variations of the light wave, from which the underlying signal and the information may be recovered.
Generally, an optical receiver collects a phase-encoded, amplitude-encoded, or frequency-encoded optical signal and performs one or more demodulation processes to convert the phase modulation, amplitude modulation, or frequency modulation into useful information. For example, this information may include communication information encoded in the particular modulation by a transmitter, information encoded in the particular modulation through interaction of the optical signal with an object, or other information about the source of the optical signal, the optical channel through which it traveled, and/or objects with which it interacted.